This invention relates to a pivotal screwed fitting for joining pipes, including a hollow body whose orientation can be adjusted and which has one or more coupling nipples. The pivotal screwed fitting further has a hollow screw which is accommodated in the hollow body and which serves to tighten the hollow body to a pipe terminal. The wall of the hollow screw is provided with ports which maintain communication, in accordance with the flow path, between the inner space of the hollow screw and an annular channel defined together by the hollow body and the hollow screw.
It is often required to join a pipe to a connection (coupling bore) whose axis extends transversely to the pipe. For this purpose it has been long known to use threaded elbow or Tee fittings screwed into the coupling bore. Such a screwed fitting is disclosed, for example, in German Pat. No. 919,622. The fitting described in this patent comprises a hollow body whose orientation may be adjusted and which has one or more coupling nipples.
In screwed fittings having an orientable body, the problem of maintaining fluid turbulence and throttle effects at the smallest possible value (or avoiding these altogether) has to be resolved. For solving this problem, the above-cited German patent teaches the provision of an inner collar on the hollow body (which carries one of more pipe coupling nipples) at its floor opening oriented towards the coupling bore of an apparatus wall. A hollow screw received in the hollow body has an externally threaded portion (which projects outwardly from a floor opening provided in the hollow body) and an outer collar. The latter firmly engages the inner collar when the hollow screw is screwed into the threaded coupling bore of the apparatus wall. In this manner a firm and fluid-tight connection is obtained between the hollow body and the hollow screw. The end face of the hollow body disposed opposite the floor opening in the hollow body is closed off in a fluid-tight manner by a screw plug. Although in this manner it is possible to provide identical cross sections for the pipe and the hollow screw so as to reduce unfavorable throttling effects, to achieve this result an additional component is necessary, namely the screw plug which, on the one hand, adds to the manufacturing expenses of the fitting and, on the other hand, makes assembly more complex.
German Pat. No. 1,074,338 discloses another pivotal screwed fitting for joining pipes which is formed merely of a hollow body and a hollow screw disposed in the hollow body for tightening the latter against the coupling bore of an apparatus. The wall of the hollow screw is provided with throughgoing ports. In order to reduce fluid turbulence and throttle effect, the hollow screw, which at the outside up to the screw threads has a cylindrical configuration, is provided at the inside of the srew head, in the bore base, either with a planar terminal wall or a drop-shaped, pointed central elevation. In case of a planar terminal wall of the bore base, however, a fluid turbulence cannot be avoided, since the transmitted fluid medium impinges on the planar closure and thus has to be deflected thereby. Although fluid turbulence can be reduced if the earlier-noted drop-shaped pointed elevation is used, the manufacture of such a bore floor is expensive; it needs special machining tools that have to be used in the course of separate, special manufacturing steps.